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Explain clearly how suspended solids are removed in the treatment of water for drinking - Leaving Cert Chemistry - Question (b) - 2008
Question (b)
Explain clearly how suspended solids are removed in the treatment of water for drinking. Identify two chemicals added at the final stages of the treatment of water ... show full transcript
Worked Solution & Example Answer:Explain clearly how suspended solids are removed in the treatment of water for drinking - Leaving Cert Chemistry - Question (b) - 2008
Step 1
Explain clearly how suspended solids are removed in the treatment of water for drinking.
Answer
Suspended solids in water are primarily removed through two main processes: sedimentation and filtration.
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Sedimentation: Initially, water is allowed to settle in a large tank, where the heavier suspended particles are able to gravity-settle to the bottom. This process is enhanced by the addition of coagulants, which help the particles clump together (flocculation), making it easier for them to settle.
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Filtration: After sedimentation, the clear water above the settled particles is passed through various filters (such as sand and gravel) to remove any remaining smaller particles. This step ensures that most of the suspended solids are eliminated, resulting in clearer and cleaner water.
Step 2
Identify two chemicals added at the final stages of the treatment of water for drinking.
Answer
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Chlorine (ClO₁): The purpose of adding chlorine is to eliminate any remaining microorganisms in the water, ensuring that the water is safe for drinking by disinfecting it.
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Sodium bicarbonate (NaHCO₃): This chemical is used to adjust the pH levels of the water. Maintaining the correct pH is essential as it prevents corrosion in pipes and ensures that the water is not too acidic or basic for human consumption.